1. Field of the Invention
The invention relates to systems and methods for producing sound inside a headgear unit, and more particularly to providing an approximation of free field hearing inside the headgear unit.
2. Background
Various types of headgear can be used in a variety of situations. For example, helmets can be used to protect a subject's head from injury during potentially dangerous physical activities, such as using a motor vehicle or participating in sports activities or military activities. In particular, military helmets can be used to protect a subject's head from injury as well as to provide a barrier against biological or chemical hazards.
However, headgear may also hinder the subject's perception of sound. Sound misperception or acoustic isolation can result in increased physical danger, for example, if a subject cannot hear spoken warnings or sounds from approaching objects. The interference between the headgear and external sound waves may result in the subject hearing sounds that are perceived as being muffled or softer than desired. It may also be difficult for a subject wearing a helmet to perceive the direction from which a sound is generated.